The present invention relates generally to electrical motor/generators, and more particularly to superconducting multi-pole electrical motor/generators.
Multi-pole electrical motor/generators are commonly used in a variety of applications, including generators in large-scale commercial power plants, and motors in small-scale electric vehicles. By way of example, a known electrical generator design includes a multi-pole rotor having a plurality of permanent magnets arranged thereon. The rotor is rotated within the electrical generator by an external drive source, such as a diesel engine. The rotating rotor creates an alternating magnetic field within the electrical generator due to the moving magnets.
The known electrical generator also includes a stator with a plurality of conductive armature windings wound thereon. Because the stator is subjected to an alternating magnetic field from the rotating rotor, an electric current is generated in the armature windings of the stator. This generated electric current can be tapped, thereby creating an electrical power source.
Electrical motor/generator efficiency, however, has been limited by the efficiency of materials used in the conductive windings for the rotor and/or stator (depending on the particular design). Copper windings, for example, experience considerable resistive losses when passing high amperage current therethrough (power loss=current2×resistivity). Hence, superconducting materials (which have a zero resistance; i.e., a resistivity substantially less than that of copper, aluminum, and other commonly used conductive materials) have been used as a winding material for creating low loss electrical motor/generators. See, for example, U.S. Pat. Nos. 6,412,289; and 6,438,969, which are both incorporated by reference herein in their entirety.
Problems exist, however, in known superconducting electrical motor/generators, including cooling the superconducting coils to cryogenic temperatures, supporting cryogenic coils while thermally isolating them from other structures within the electrical motor/generator, and reducing the cost, complexity, size, and weight of the electrical motor/generator.